The election of the far-right populist Jair Bolsonaro in the 2018 Brazilian Presidential election was a major turning point in the history of the country and arguably part of a worldwide trend toward a form of ‘authoritarian populism’. The present study was conducted to explore psychological factors that may contribute to the appeal of a polarizing figure such as Bolsonaro, in particular, to determine whether measures of various ‘Moral Foundations’ or ‘Social Dominance Orientation’ (SDO) could best predict voting behaviour in the 2018 election. Given the cultural and economic context in Brazil, measures of religiosity and personal relative deprivation were included as additional potential explanatory variables. An online survey of 325 people from Brazil found that Bolsonaro voters scored higher on the ‘binding’ (Loyalty, Authority, Purity/Sanctity) and lower on the ‘individualizing’ (Care, Fairness) Moral Foundations than voters for the candidate of the left, Fernando Haddad. Moreover, Bolsonaro voters scored higher than Haddad voters on SDO and religiosity. When the various social, moral and religious measures were considered simultaneously in a binary logistic regression, it was endorsement of right-wing authoritarian ideologies (SDO and the Authority Moral Foundation), rather than lack of endorsement of individualizing Moral Foundations that best distinguished Bolsonaro voters.